whitney



(No Model.) 2 Sheets-Sheet -1. A. WHITNEY.

LATHB HEAD.

Patented June 9, 1885.

(No Model.) 2 Sheets-Sheet 2.v

A. WHITNEY.

. LATHE HEAD. v No. 319 650. Patented June 9,1885.

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N. PETERS Phuto-Uthngrlpher. Wnhillgn. D. (l

AMOs WHITNEY, OE HARTFORD, CONNECTICUT, AssIGNOR TO THE PRATT a WHITNEY COMPANY, OE SAME PLACE.

LATHE-HEAD.

{EI-ECI'ICATION forming part of Letters Patent No. 319,650, dated June 9, 1885.

Application led March 27, 1885. (No model.)

To all whom it may concern.-

Be it known that I, AMOs WHITNEY, a citi- Y zen of the United States'of America, residing in the city and county of Hartford, State of Connecticut, have invented certain new and useful Improvements in Lathe-Heads,of which the following is a specification, reference being had to the accompanying drawings, in which- Figure lis a longitudinal vertical sectional view through the center of the lathe-.spindle of a lathe-head embodying my improvements. Fi g, 2 is an elevation of upper part of the front end of the same, which is at the left` hand in x 5 Fig. l. Fig. 3 shows a cross-section of the lathe-spindle in line XX, Fig. l. Fig. 4 shows a modification of Fig. l. Figs. 5, '6, 7, and 8 illustrate the state ofthe art, as hereinafter referred to.

Similar letters refer to the same parts throughout the several views.

This invention relates more particularly to latheheads for engine-lathes, but it is applica ble to machines in general in which the spindles are required to run extremely free from end-play. vIt is well known to builders of fine machinery, especially of such as runs at high velocities, that this result is alwaysaccomplished with difficulty, which becomes more and more serious as the length'of the spindle is increased. The difficulty is caused, principally, by the heating of the parts, especially the spindle, by the friction of their bearingsurfaces or otherwise, which, owing to the different coefficients of expansion of different materials,varies the relative adjustment of the parts according to their temperature. This adj ustment is also affected by the varying strains upon the parts, due to working the machine, 4o which strains necessarily spring some parts more than others. In the coarser kinds of machinery, where some end-play is not so objectionable, it has been customary to make the spindle with collars upon each side of each 45 bearing, asin Fig. 5, to receive the pressure.

In engine-lathes asecond form of spindlesCillustrated by Fig. 6) has generally been used with such collars or shoulders on each side of the front bearing and a step at the back end. 5o This construction (which is too well known to require a more particular description) for ne, close-tting machinery is particularly objectionable, as any expansion of the spindle, when the step is set up closely, causes an undue friction against the inner one of the collars, thereby heating the spindle and still further increasing the difculty. To obviate those objections spindles are frequently made with no collars against the front bearing, but with one collar on each side of the back bear- 6o ing, as shown in Fig. 7. This Inode of construction reduces the difficultyarising from the longitudinal expansion of the spindle in about the same proportion that exists between the length of the back bearing and that length plus the distance between the bearings. (It will be explained hereinafter how I make the corresponding surfaces much nearertoget-her.) This allows the front journal to slide through the front bearing without resistance therefrom. 7o

It is customary to construct the bearings for such spindles, as above described ,in two parts, so that as the surfaces of the journal and jourA nalbearing wear away the two parts may be brought more closely together to correct any inaccuracy arising from such wearing away; but that mode of correction introduces another difculty hardly less serious than the previous one-to wit, the axis of the spindle is gradually lowered, so that the original and 8o proper alignment of the partslis lost and the machine to that extent depreciated in value.

Where the exact alignment of the spindle is very essential, its journals and bearings have frequently been made of the form of truncated 8 5 cones, so that any wear of the journal could be. perfectly corrected and their perfect alignment maintained by a slight longitudinal adjustment of the step or back bearing. This plan, which is extensively employed, and has 9o the advantage of permitting the use of solid bearings, restores the difficulty aforesaid arising from thermal changes which characterized spindleNo. 2, above described. In effect, one ditculty is merely substituted for another. It is obvious, therefore, from these references to the state of the art that while each of the spindles No. 3 and No. 4 asheretofore constructedhave important advantages, these advantages naturally stand in opposition to each other, thereroo by seriously impairing the utility of those forms of spindles. It is the object of my in vention to overcome this opposition and furnish a construction which shall secure in one spindle the advantages, respectively, of both of those. j

To this end my invention consists in certain combinations of mechanism, which I will rst describe in connection with the drawings, and afterward specifically point out in the claims.

In the drawings forming apart of this specification, A is the frame ot' a lathe-head, of the usual or any suitable form, which may have the caps M and N, (or these parts may be formed integrally with the frame,) and is bored to receive the front bearing, B, and the back bearing, L. The back bearing, L, is rigidly fixed into the frame by means of the nut V. The front bearing, B, is fitted into the frame l closely, but not so rigidly as to prevent lon- Vtapered bearing B.

gitudinal movement, and if of a cylindrical form is kept from rotating by a key, as E, or by an ordinary set-screw. BearingBis bored tapering to receive the conical journal C of the spindle S. .That journal may be a suitably-formed portion of the spindle itself, as in Fig. 4, or may be made separately from the spindle and adjustably secured thereto, as in Fig. 1.` Some parts of my invention, however, are not limited to this latter mode of constructing said journal, but, on the contrary, will permit it to be formed as in said Fig. 4. When made separately, this journal` is of a tubular form, bored cylindrically to tit and slide on the spindle, and turned to fit the If the tube Gis not tit` ted to the spindle closely enough tofprevent it from turning thereon, then some device, asy keyD, should be employed to so prevent it. A nut, F, is provided for adjusting tubular journal C on the spindle, so as to slide thei bearing B within the frame and against the fixed collar J. When the journal C is made integrally with the spindle, the nut F acts to slide the bearing, as in Fig. 4, instead of the journal, as in Fig. l.

By means of the aboveedescribed construction it is obvious that all lateralplay of the journal in its bearing may be taken up and the bearing slide freely through its support in the frame to accommodate the variations of the-length of thespindle due to thermal changes or othery cause. It will also be evident that the position relative to the spindle of journal C, bearing B, nut F, and collar .I may be reversed without affecting the operation of this part of `my invention. Furthermore, itV will be understood that this front journal and bearing may be used independently of the back bearing, hereinafter described, in connection with other kinds of bearings.

The back bearing,'L,is bored tapering to receive the' conicalv journal K, which is similar to journal C, vand it is held in place by nut Gr` and key I, which are similar, respectively, to nut F and key D.

A spindle end, P, is secured to the spindle, and has two bearing surfaces-one at W, which runs against bearing Lsimilarly as collar J runs against bearing B, and the other at X, which runs against the step T. This step is of the usual description, and is used and clamped in position by nut R in the usual manner. The parts of this back journal and bearing are of course capable of the same modications as the corresponding parts of the front journal and bearing. HWhen thus modified, as shown in Fig. 4, the lateral play of the back journal is taken up by shortening the spindle at that end and screwing end piece, P, up to the newsurface thus formed.

I have described and shown bearings B and L as being made of a cylindrical form; but they are not necessarily so made. They may have externallyV a rectangular 'crosssectional form, and may be made in two parts secured together; but there is,in myopinion, no advantage to be gained thereby.

Having thus described my invention, I claim- 1. The combination of a suitable framework havingany suitable back bearing adapted to receive one end of a spindle and to preven't the longitudinal movement thereof, a

spindle having a back journal corresponding to Said back bearing and a conical front jourf nal, substantially as described, and a front bearing fitting said conical front journal and adapted to slide in said frame, substantially as set forth.

2. The combination of a frame, as A, spindle S, having journal C and nut F, bearing against said journal, and sliding bearing B, substantially as described.

3. The combination of'a frame, as A, spindle S, collar J, tubularjournal C, nut F, and bearing B, substantially as described.

4. The combination of -a frame, as A, spindle S, having journalv C andnut F, bearing against said journal, a tubular sliding bearing, B, and keyE, substantially as described.

5. The combination of bearing L, a spindle having a conical journal, K, and spindle end P, nut V, and step T, substantially as and for the purpose described.

6. The combinationiof bearingL, a spindle having the tubular 'conical journal K, nut G, and spindle end P, the nut V, and step T, substantially as and for the purposedescribed.

7. In a lathelhead, the combination of a suitable frame, as A, anda spindle, as S, having conical journalsOfand K, nut F, and'spi'ndle end P, bearings B and L, nut V, an'dstep T, all constructed'and arranged to operate substantially as-described. j

AMOS WHITNEY. VVitnesses:

F. H. RICHARDS, H.- FFL. ORCUTT.

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